Whose to blame for people not caring about privacy anymore? Is it the zoomer generation? Why does Gen Y care privacy concious and care more about privacy than zoomers?

Because no one uses Windows 11

The real answer isn't necessarily Microsoft related, it's a psychological/cultural paradigm shift of the personal identity.
For us, it was generally accepted that the online you and the real you were two distinct things, mainly to protect your real identity and personal/financial information. There came an automatic suspicion towards anyone that wanted to merge those.
But social media has generally erased the boundary between the online you and the real you, in fact many people prefer to see their online self as more genuine and so the eradication of privacy at the cost of connection and the almighty algorithm is seen as a necessary and irrelevant cost of participation. Zoomers will walk around with a face mask and clothes that make them look like a celeb trying to escape paparazzi while at the same time disclosing every personal thought to millions of people.
A complete inversion of the real conditions of life.
Think of it, we grew up seeing the rise of Google emerge from just another search engine to an integral part of life if you're involved in any kind of education/employment etc. To Zoomers, all these companies are just as necessary and the ToS are like accepting you'll get wet when it rains.